More and more use is being made of electronic maps, e.g., routing, navigation, finding addresses, and points of interest. New uses are continually appearing. As a consequence of these map uses, the necessity to identify changes in the real world and reflect that change in the electronic map data in a timely fashion becomes more important as these uses advance in technology.
In the past updating mapping data has been a very difficult, time consuming and expensive task, with some items failing to be promptly entered and other items being entered erroneously. For example, road map databases for a country the size of the US are enormous. They represent hundreds of millions of individual facts. Man and nature are continuously changing or adding to those facts. Mapping companies are continuously looking for new methods to find changes, or even an indication of change, so they may more effectively research the issue and update the electronic map.
In recent years, new technologies have come on line including, aerial and satellite photography, terrestrial based imagery from Mobile Mapping Vehicles, GPS and other position determination equipment and their enhancements, GIS platforms and spatial database engines to facilitate making and housing the changes, Lidar, Laser Scanners, radars and, of course, the Internet. These technologies have helped create map updates faster, cheaper, and more accurate, and have also enabled maps to carry new forms of information such as 3D buildings and the like.
Portable navigation devices (PNDs) that include GPS (Global Positioning System) signal reception and processing functionality are well known and are widely employed as in-car or other vehicle navigation systems. Such devices are of great utility when the user is not familiar with the route to the destination to which they are navigating. The wide use of PND's and other navigation devices has increased the availability of data acquisition devices for use in creating map updates.
However, errors in road characteristics defined by one or more attributes associated with road segments are either discovered only by driving to the area in question with a mobile mapping van, by customer report of the error, or by routine quality checks that compare the map database to new source material, such as a local map, air photo, etc.